1. Field of the Invention
This device relates to a suction catheter, and more particularly to a endotracheal suction catheter.
2. Description of Related Art
A typical conventional endotracheal suction catheter is shown in FIGS. 1 and 2. The suction catheter is adapted to remove deposits in a trachea or bronchial tube through suction force generated by a reduced or vacuum pressure in the catheter lumen. The suction catheter is inserted through a trachea and a bronchial tube. Thereafter, vacuum pressure is applied to the catheter lumen which vacuum pressure is transferred to the deposit causing it to be moved into the catheter lumen. According to the ordinary use of the suction catheter, some medical operations such as supplying oxygen are temporarily stopped as the endotracheal suction catheter is positioned and during the deposit removing operation.
As best shown in FIG. 1, suction catheters 1 typically have an elongated tube portion 2, that is usually a tubular member made of polyvinyl chloride (PVC) or similar material enclosing a lumen 3 extending substantially from the proximal end 4 to the distal end 5 of catheter 1. Proximal end 4 is inserted into a body lumen A of a patient such as the trachea or a bronchial tube (see FIG. 2). Lumen 3 is connected to a pressure reducing means such as a vacuum source (not shown) at the distal end 5 of catheter 1 for reducing pressure in the lumen 3 of the catheter 1.
A hand assisting part 6 is formed at the distal end 5 of the catheter 2. Hand assisting part 6 allows the operator of catheter 1 to move and manipulate catheter 1 during insertion and removal of the catheter 1 from the body lumen A of a patient as well as while catheter 1 is in use in the patient's body. Often the hand assisting part 6 is made integrally with the suction catheter 1 and may be shaped as a small partly swelled bulb.
An end opening 7 is formed in the proximal end 4 along the axis of tube portion 2. End opening 7 places the lumen 3 directly in fluid communication with body lumen A. An annular flange 8 having an outer diameter larger than the outer diameter of tube portion 2 is located around the proximal end 4 of catheter 1. The central axis of flange 8 is aligned with the axis of tube portion 2 and flange 8 extends radially away from tube portion 2.
There are several side holes 9 formed in the tube portion 2 of the catheter 1 near flange 8 fluidly connecting lumen 3 with the exterior of tube portion 2. Side holes 9 are located along tube portion 2 near but on the distal side of flange 8. Side holes 9 combine with end opening 7 to form a suction mouth at distal end 5. A suction control hole 10 is formed at the distal end 5 of catheter 1 near the hand assisting part 6. Suction control hole 10 extends from lumen 3 to the exterior of tube portion 2. When suction control hole 10 is open, vacuum pressure in lumen 3 escapes through control hole 10. When vacuum pressure in lumen 3 escapes through control hole 10, the vacuum pressure is prevented from being available at end opening 7 and side holes 9. By placing a thumb or other finger over suction control hole 10, vacuum pressure in lumen 3 is prevented from escaping from lumen 3 at control hole 10, thereby presenting vacuum pressure to end hole 7 and side holes 9. Covering and uncovering suction control hole 10 controls the vacuum pressure within lumen 3.
FIG. 2 is a schematic cross-section view of the prior art catheter of FIG. 1 in use in a body lumen A. The proximal end 4 is inserted into the body lumen A and vacuum pressure is applied to lumen 3 at distal end 5. When suction control hole 10 is closed as described above, an air pressure difference is created between lumen 3 and the body lumen A causing air in body lumen A to flow in layers toward proximal end 4. This air flowing in layers is divided into two streams. One stream enters end opening 7 and flows straight through lumen 3 to the source of vacuum pressure. The other stream flows through the gap between the outer periphery of the flange 8 and body lumen A and enters lumen 3 through the side holes 9. The flowing air causes deposits in the body lumen A near flange 8 to be removed and brought into lumen 3 through end opening 7 and side holes 9. Once the deposits are in lumen 3, they are subsequently moved out of the catheter 1 at the distal end 5 by being caught or engulfed in the air flowing through lumen 3.
Characteristics desirable for the suction catheters are:
(a) Ordinarily, the catheter is quickly operated, so it must have a strength or rigidity and stiffness sufficient to prevent the suction catheter from bending and twisting during insertion and operation; PA1 (b) the catheter should be able to suck and effectively remove deposits through a suction mouth at the proximal end; PA1 (c) because the proximal end is apt to strike a trachea or bronchial tube during insertion and operation, it is preferable to make the proximal end of the catheter as soft and flexible as possible to avoid producing an injury and bleeding to the trachea or bronchial tube; and, PA1 (d) also, it is desirable that the shape of the proximal end not stick the trachea or bronchial tube resulting in injuries and bleeding.